OFFSET
1,1
COMMENTS
Conjecture: for n >= 5, a(n) = ((7/2) * (7 - (4 * sqrt(2))) * (1 + sqrt(2))^n) - (8 * n) - 2 + ((7/2) * (7 + (4 * sqrt(2))) * (1 - sqrt(2))^n). Confirmed to n = 13, and known to be an upper bound for all larger n.
REFERENCES
Mark Manasse et al., The Panex puzzle, in Tribute to a Mathemagician, Peters, 2005, pp. 145-161.
LINKS
N. Baxter, Panex Puzzle Resources.
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
William Rex Marshall, Aug 19 2005
EXTENSIONS
a(9) (found by David Bagley in 2008) and a(10)-a(13) (found by Derek Kisman in 2010) communicated by William Rex Marshall, May 27 2011
STATUS
approved